ard and
wrapped three or four times round the mast M1, which should have several
notches in its front edge, to assist the setting of the elevator at
different angles. Pull the wire tight, so that the elevator shall maintain
a constant angle when once set. H H1 is a piece of 25 to 30 gauge wire bent
as shown and fastened by binding. It passes round the front of the rod, in
which a little notch should be cut, so as to be able to resist the pull of
the twin rubber motors, the two skeins of which are stretched between H H1
and the hooks formed on the propeller spindles. If all these hooks are
covered with cycle valve tubing the rubber will last much longer. The
rubber skeins pass through two little light wire rings fastened to the
underside ends of HS2. (Fig. 133.)

The front skid or protector, FS, is made out of a piece of thin, round,
jointless cane, some 9 inches in length, bent round as shown in Fig. 134,
in which A B represents the front piece of the T-shaped rod and x y z a the
cane skid; the portion x y passing on the near side of the vertical part of
the T, and z a on the far side of the same. At E and F thread is bound
right round the rod. Should the nose of the machine strike the ground, the
loop of cane will be driven along the underside of the rod and the shock be
minimized. So adjust matters that the skid slides fairly stiff. Note that
the whole of the cane is on the under side of the top bar of the T.

[Illustration: FIG. 134.--Front skid and attachment to backbone.]

Bearings.--We have still to deal with the propellers and their bearings.
The last, TN and TNl (Fig. 133), are simply two tiny pieces of tin about
half a gramme in weight, bent round the propeller spar HS3 at B and B1.
Take a strip of thin tin 1/4 inch wide and of sufficient length to go
completely round the spar (which is 1/4 by 1/8 inch) and overlap slightly.
Solder the ends together, using a minimum amount of solder. Now bore two
small holes through wood and tin from rear to front, being careful to go
through the centre. The hole must be just large enough to allow the
propeller axle to run freely, but not loosely, in it. Primitive though such
a bearing may seem, it answers admirably in practice. The wood drills out
or is soon worn more than the iron, and the axle runs quite freely. The
pull of the motor is thus directed through the thin curved spar at a point
where the resistance is greatest--a very important matter in model
aeroplane construc